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Briefly introduction to image/ video coding standard and FGS for MPEG-4

Briefly introduction to image/ video coding standard and FGS for MPEG-4. 卓傳育. Video Compression Standards. ITU-T International Telecommunication Union — Telecommunication Standardization (ITU-T) MPEG Moving Picture Experts Group.

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Briefly introduction to image/ video coding standard and FGS for MPEG-4

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  1. Briefly introduction to image/ video coding standard and FGS for MPEG-4 卓傳育

  2. Video Compression Standards • ITU-T • International Telecommunication Union — Telecommunication Standardization (ITU-T) • MPEG • Moving Picture Experts Group

  3. International Telecommunication Union — Telecommunication Standardization (ITU-T) • CCITT H.261 • ITU-T Study Group 15 • Videophone and video conferencing • 1988-1990: p x 64 kbps (p = 1… 30) • ITU-T H.263 • PSTN and mobil network: 10 to 24 kbps • 1994: H.263, H.263+… • ITU-T H.26l • Merging to JVT in MPEG-4 Part 10

  4. MPEG: Moving Picture Experts GroupCoding of Moving Video and Audio MPEG-1: CD-I, for Digital Storage, … -1992 MPEG-2: … + TV, HDTV, for Broadcast –1994 MPEG-3: HDTV -> merged into MPEG-2 MPEG-4: Coding of Audiovisual Objects-V.1:1998; V.2:1999 Extensions ongoing MPEG-7: MM Description Interface – Fall 2001 ‘Describing’ audiovisual material MPEG-21: Digital Multimedia Framewrok – 1st parts early 2002 ‘The Big Picture and The Glue’

  5. Block-Based Coding • Why divide to blocks? • Image->Blocks

  6. H.261 Video Formats Y pixel Cb, Cr pixel Block boundary

  7. Arrangement of H.261 352 176 176 176 48 48 288 QCIF CIF

  8. Arrangements of data structure in H.261 176 176 144 48 GOB (Group Of Block) QCIF picture 8 16 8 8 8 16 MB (Macro Block)

  9. Transform coding • Encoder • Decoder Transform Coefficients Zigzag Scan (2D->1D) Image block Bitstream T Q Entropy coding T-1 Q-1 Entropy coding Bitstream Reconstructed Image block Reconstructed Transform Coefficients Inverse Zigzag Scan (1D->2D)

  10. -415 -29 -62 25 55 -20 -1 3 7 -21 -62 9 11 -7 -6 6 -46 8 77 -25 -30 10 7 -5 -50 13 35 -15 -9 6 0 3 11 -8 -13 -2 -1 1 -4 1 -10 1 3 -3 -1 0 2 -1 -4 -1 2 -1 2 -3 1 -2 -1 -1 -1 -2 -1 -1 0 -1 Example of DCT 52 55 61 66 70 61 64 73 63 59 66 90 109 85 69 72 62 59 68 113 144 104 66 73 63 58 71 122 154 106 70 69 67 61 68 104 126 88 68 70 79 65 60 70 77 68 58 75 85 71 64 59 55 61 65 83 87 79 69 68 65 76 78 94 DCT

  11. -415/16 = -26 -415 -29 -62 25 55 -20 -1 3 7 -21 -62 9 11 -7 -6 6 -46 8 77 -25 -30 10 7 -5 -50 13 35 -15 -9 6 0 3 11 -8 -13 -2 -1 1 -4 1 -10 1 3 -3 -1 0 2 -1 -4 -1 2 -1 2 -3 1 -2 -1 -1 -1 -2 -1 -1 0 -1 • 16 11 10 16 24 40 51 61 • 12 12 14 19 26 58 60 55 • 14 13 16 24 40 57 69 56 • 14 17 22 29 51 87 80 62 • 18 22 37 56 68 109 103 77 • 24 35 55 64 81 104 113 92 • 49 64 78 87 103 121 120 101 • 72 92 95 98 112 100 103 99 Example of JPEG Coding(Encoder)

  12. -415 -29 -62 25 55 -20 -1 3 7 -21 -62 9 11 -7 -6 6 -46 8 77 -25 -30 10 7 -5 -50 13 35 -15 -9 6 0 3 11 -8 -13 -2 -1 1 -4 1 -10 1 3 -3 -1 0 2 -1 -4 -1 2 -1 2 -3 1 -2 -1 -1 -1 -2 -1 -1 0 -1 Example of JPEG Coding(Encoder) -26 -3 -6 2 2 0 0 0 1 -2 -4 0 0 0 0 0 -3 1 5 -1 -1 0 0 0 -4 1 2 -1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

  13. 2D->1D -26 -3 -6 2 2 0 0 0 1 -2 -4 0 0 0 0 0 -3 1 5 -1 -1 0 0 0 -4 1 2 -1 0 0 0 0 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 -26 –3 1 –3 2 –6 2 –4 1 –4 1 1 5 0 2 0 0 –1 2 0 0 0 0 0 –1 –1 EOB Example of JPEG Coding(Encoder) Transform coding(DCT) Quantization Zigzag Scan Entropy Coding (bit stream)

  14. Encoder For Video Sequence Transform Coefficients Zigzag Scan (2D->1D) Image block Bitstream T Q Entropy coding - MC T-1 Q-1 Reconstructed Image block Reconstructed Transform Coefficients Video Compression • Encoder For Still Image

  15. H.261 • Intra frame • 傳整個frame的information • Inter frame • 會reference上一張frame • 傳motion vector • 傳差值

  16. H.261 Coder Video in DCT Q Inverse Q Inverse DCT Loop Filter Motion Compensation

  17. Motion Estimation (22,20) (32,16) (-10,4) Current frame Referenced frame Macro block 16*16 31*31

  18. Current original frame Full-search algorithm Maximum check： 31*31=961 Current referenced frame

  19. Current original frame 3-step search algorithm 距離8->4->2->1 maximum check： 1+8+8+8+8=33 Current referenced frame

  20. NTSS(new 3-step search) algorithm -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7

  21. FSS(4-step search) algorithm -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7

  22. BBGDS -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7

  23. Overview of Fine Granularity Scalability inMPEG-4 Video Standard Weiping Li, Fellow, IEEE

  24. Illustration of video coding performance

  25. Multi-layer Coding

  26. SNR scalability decoder defined in MPEG-2

  27. Layered scalable coding Tech. • Temporal scalability

  28. Layered scalable coding Tech. • Spatial scalability

  29. BIT-PLANE CODING OF THE DCT COEFFICIENTS

  30. BIT-PLANE CODING OF THE DCT COEFFICIENTS

  31. FGS USING BIT-PLANE CODING OF DCT COEFFICIENTS • Overall Coding Structure of FGS • Some Details of FGS Coding • Profile Definitions in the Amendment of MPEG-4

  32. Overall Coding Structure of FGS FGS encoder structure

  33. Overall Coding Structure of FGS FGS decoder structure

  34. Some Details of FGS Coding • Different Numbers of Bit-Planes for Individual Color Components • Variable-Length Codes • Decoding Truncated Bitstreams

  35. Different Numbers of Bit-Planes for Individual Color Components

  36. Variable-Length Codes • Statistics of the (RUN, EOP) symbols in the four VLC tables

  37. Coding patterns for syntax element fgs_cbp

  38. Coding patterns for syntax element fgs_cbp

  39. Decoding Truncated Bitstreams • Decoding of the truncated bitstream is not standardized in MPEG-4. • One possible method • To look ahead 32 bits at every byte-aligned position in the bitstream. • If the 32 bits are not fgs vop start code, the first 8 bits of the 32 bits are information bits of the FGS frame to be decoded. The decoder slides the bitstream pointer by one byte and looks ahead another 32 bits to check for fgs vop start code.

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